From step + -wise.

stepwise (not comparable)

1. One (small) step or stage at a time; gradual; piecemeal

   Synonyms: step-by-step

   • 2003, Steven Scott Phelps, tRNA interactions in the ribosomal A-site […], page 48:

     The act of translation requires the stepwise decoding of the mRNA one codon at a time.

stepwise

1. One step or stage at a time; step by step

• in order, step by step; see also Thesaurus:sequentially or Thesaurus:incrementally

• German: schrittweise